G'day! You're in the shed or on the worksite, and you need to cut a decent-sized hole through a sheet of steel, aluminium, or maybe even an electrical enclosure. Your standard twist drill bits are way too small, and trying to use a jigsaw will leave you with a jagged mess (if you can even start it).

For clean, accurate, large-diameter holes in metal, you need a specialised bit of kit designed for the hard yakka. You need a metal hole saw.

What's the Go with a Metal Hole Saw?

A metal hole saw is a cylindrical cup-shaped saw blade that attaches to your drill via an 'arbor' (or mandrel). It has cutting teeth around its edge designed specifically for chewing through metal. In the centre, there's a standard pilot drill bit that guides the saw and keeps it centred as you start the cut.

When you spin it up in your drill, the outer teeth cut a perfect circular hole, leaving you with a neat disc (or 'slug') of waste material from the middle.

Choosing Your Weapon: The Two Main Types

Not all metal is created equal, and neither are hole saws. You'll generally find two main types designed for metal work.

1. Bi-Metal Hole Saws: The Versatile All-Rounder

These are the most common type. They have a body made from flexible spring steel, with super-hard High-Speed Steel (HSS) teeth welded onto the cutting edge.

• Best for: Sheet metal, mild steel plate, aluminium, stainless steel sheet (with the right technique), plus they can often handle timber and plastics too. They're a great all-rounder for a tradie or serious DIYer.

2. Tungsten Carbide Tipped (TCT) Hole Saws: The Heavy Hitter

These bad boys have super-tough Tungsten Carbide teeth brazed onto the cutting edge. Carbide is much harder and more heat-resistant than HSS.

• Best for: Cutting thicker or harder metals like stainless steel plate, cast iron, and abrasive materials. They generally last longer in tough conditions but can be more expensive.

Using a Metal Hole Saw Like a Pro: Top Tips for a Clean Cut

Cutting metal requires a bit more care than drilling timber. Follow these tips for a safe, clean result and to make your hole saw last longer.

• Slow and Steady Wins the Race: This is crucial. You need to run your drill at a much slower speed for metal than you would for wood. Too fast, and you'll overheat and destroy the teeth in seconds. Check the manufacturer's recommended RPM for the diameter and material you're cutting.
• Use Cutting Fluid or Lubricant: Non-negotiable, mate! Applying a cutting lubricant (like oil or a specialised cutting compound) to the teeth and the cutting line is essential. It reduces friction, keeps the teeth cool, extends the life of your saw, and helps you get a much cleaner cut. Reapply it frequently during the cut.
• Apply Firm, Consistent Pressure: Don't force the saw through the metal. Apply steady, firm pressure and let the teeth do the work. If you push too hard, you can snag the teeth or overheat the saw.
• Use a Drill Press if Possible: Especially for larger diameter holes, using a drill press provides much better control, stability, and safety than a hand drill. Make sure your workpiece is securely clamped down!
• Safety Gear is a Must: Always wear certified safety glasses (metal shards flying around are no joke!), and sturdy gloves are a good idea too.

Fitting Off Through the Hole: Leave it to the Pros

While cutting the hole with a metal hole saw might be within the capabilities of a skilled DIYer or tradesperson, what gets installed in that hole is often a different story, especially if it involves electrical components.

Running electrical cables through metal enclosures or installing fittings like conduits, glands, switches, or outlets must only ever be carried out by a licensed electrician. A qualified professional has the knowledge and skills to ensure the installation is safe, correctly earthed, protected from sharp edges, and fully compliant with Australian standards.

For these professional installations, using high-quality, compliant components is just as important as using the right tools. Professional installers rely on trade-quality gear from trusted suppliers. Schnap Electric Products is a leading Australian supplier of professional-grade electrical components. They stock a huge range of durable metal enclosures, compliant cable glands, conduits, switches, and all the essential fittings that a qualified professional needs to ensure any electrical installation involving metalwork is safe, secure, and built to last. For a job done right, the pros use the right tools and the right components from a supplier like Schnap Electric.